Typically the size of optical transceiver modules are chosen by multiple suppliers in a consortium known as a multi-sourcing agreement (MSA). The MSA determines the specifications of the transceiver after considerable engineering effort is expended. Attributes, such as the physical size, are determined by the power dissipation of the module and typical customer cooling capabilities. Other factors contributing to the design process include the maturity of the internal technology needed to build the module, i.e. newer technology tend to be smaller and consume less power, but are less likely to be readily available in the marketplace quickly.
Currently, optical transceivers with data rates up to 4 Gb/s are packaged in small form factor (SFF or SFP) packages, while optical transceivers with higher data rates, e.g. 10 Gb/s, are in larger packages, such as XFP, X2, and XENPAK. A conventional XFP arrangement is illustrated in FIG. 1, in which an XFP transceiver module 1 is plugged into a host cage assembly 2 mounted on a host circuit board 3. The host cage assembly 2 includes a front bezel 4, a cage receptacle 5, and a host electrical connector 6. The transceiver module 1 is inserted through an opening in the front bezel 4, and through an open front of the cage receptacle 5, until an electrical connector on the transceiver module 1 engages the host electrical connector 6. The cage receptacle 5 has an opening 7 in the upper wall thereof through which a heat sink 8 extends into contact with the transceiver module 1 for dissipating heat therefrom. A clip 9 is provided for securing the heat sink 8 to the cage receptacle 5 and thereby into contact with the transceiver module 1. With this arrangement, the heat sink 8 can be changed to suit the owners' individual needs without changing the basic transceiver module 1.
Currently, there is motivation in the industry to extend the SFF/SFP package to 8 Gb/s or even higher data rates; however, considerable concern has been expressed on both temperature and EMI performance as well as how the large power consumption will limit the density of usage and/or the number of reaches (LR, ER, etc) available.
An object of the present invention is to overcome the shortcoming of the prior art by providing an optical transceiver arrangement that will support both very high data rates and very high density applications.